WP showing feeds instead of pages

I’ve searched through the discussions without finding a solution, please link me a solved topic if I haven’t been able to find it.

My problem is that now and then worpdress shows feeds instead of pages, when I refresh the page everything goes fine but if I click on another link on the menu 50% chances are that I’ll se feeds again untile I refresh!

I read somewhere that it could be a problem of invalid xhtml but I checked and passed validation.

This happens in all the sites I put up with 2.8 version.

Please help